000 AGXX40 KNHC 180757 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 400 AM EDT WED APR 18 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... WEAK COLD FRONT EXTENDS FROM DEVELOPING LOW PRES 1014 MB AT 30N88W TO 18N93W. WEAK HIGH PRES 1022 MB OVER SW N ATLC HOLDS ITS POSITION FORCING FRONT TO SHIFT NE AND DISSIPATE TONIGHT AND THU. STRONG CONVECTION REMAINS ASSOCIATED WITH COLD FRONT N OF 24N BUT DIMINISHING IN STRENGTH AND COVERAGE TONIGHT AND THU. ATLC RIDGE MAINTAINS STEADY LIGHT SE TO S BREEZE THROUGHOUT MOST OF GULF WATERS FRI AHEAD OF SECOND...AND STRONGER...COLD FRONT ENTERING NW GULF ZONE FRI NIGHT. FRONT QUICKLY REACH FROM 1004 MB LOW PRES NEAR SE LOUISIANA TO 18N95W EARLY SAT WITH STRONG TO NEAR GALE FORCE N TO NW WINDS BEHIND IT. COLD FRONT MOVES E OF BASIN LATE SUN LEAVING GULF WITH STRONG NW WINDS AND SEAS TO 15 FT SUN. CONFIDENCE ON FRONT PERFORMANCE IS FAIRLY HIGH GIVEN THAT DYNAMICAL GUIDANCE IS IN GOOD AGREEMENT WITH BOTH TIMING AND STRENGTH OF FEATURES...WIND SPEEDS AND SEA HEIGHTS...WITH LITTLE OR NO CHANGES FROM RUN TO RUN. CARIBBEAN SEA... REMNANT OF SHEAR LINE S OF 15N E OF 80W STILL MAINTAIN FRESH E BREEZE THROUGH LATE TODAY. BY THU HIGH PRES RIDGE OVER SW N ATLC MAINTAIN LIGHT TO MODERATE TRADES ACROSS MOST OF BASIN E OF 80W AND LIGHT SE BREEZE W OF 80W THROUGH SAT WITH SEAS NO HIGHER THAN 6 FT. GULF OF MEXICO COLD FRONT APPROACHES YUCATAN CHANNEL SAT NIGHT WITH WINDS VEERING S AND SW INCREASING ABOVE 20 KT AND SEAS BUILDING TO 9-10 FT BY LATE SUN. COLD FRONT CROSS YUCATAN CHANNEL SUN AND REACH FROM SE CUBA TO SE COAST OF NICARAGUA LATE SUN. TROPICAL N ATLC S OF 19N W OF 55W... REMNANTS OF SHEAR LINE BECOME ILL-DEFINED AND ONLY MODERATE DECAYING NE SWELL REMAIN THROUGH THU. LIGHT TO MODERATE TRADES VEER MORE TO THE E WITH SWELL SUBSIDING TO 5 FT N OF 15N AND 6-7 FT S OF 15N THROUGH SUN. SW NORTH ATLC S OF 31N W OF 55W... WEAKENING HIGH CENTER AT 29N75W NOW DOWN TO 1022 MB WILL KEEP MODERATE E TO SE BREEZE WITH SEAS 3-5 FT ACROSS MOST OF BASIN THROUGH EARLY SAT. WINDS START TO PICK UP LATE SAT BECOMING STRONG S WINDS WITH SEAS 6-8 FT BY LATE SAT AND STRONG TO NEAR GALE FORCE WINDS WITH SEAS UP TO 15 FT BY SAT NIGHT AND SUN. NOTE... EFFECTIVE APR 3, 2012 AT 1800 UTC THE OFFSHORE WATERS FORECAST ZONES CHANGED FOR THE CARIBBEAN AND SW N ATLANTIC AND THE GULF OF MEXICO. ISSUANCE TIME FOR THE GULF OF MEXICO OFFSHORE WATERS FORECASTS IS REFERENCED TO THE EASTERN TIME ZONE. FOR DETAILS SEE WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE). GULF OF MEXICO... .NONE. .CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. .SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER WALLY BARNES